Vanadia aerogels

Ferrocene doping provides an electrochemical probe of the material during gelation, reporting in particular on the mobility of the probe as measured by the diffusion coefficient.133,134 If necessary the sol-gel material can be loaded with carbon powder to confer electrical conductivity (composite ceramic carbon electrodes, CCEs).135 Single-walled nanotubes in vanadia aerogels exhibit high capacities for lithium intercalation.136... 

Effect of Vanadia in Titania versus Vanadia on Titania. Rate data in Table n show that the titania-vanadia aerogel, sample (V-T)10, is intrinsically more active than the titania-supported vanadia, sample lOV/T, on a vanadia content basis. This is despite the fact that in the case of (V-T)10 some of the vanadia probably remains in the bulk after heat treatment, and thus not available for catalysis. This result suggests that for an active SCR vanadia catalyst we may actually need vanadia species in close proximity with, and not necessarily supported on, crystalline titania. 

Luo H, Churu G, Fabrizio EF, Scbnobrich J, Hobbs A, Dass A, Mulik S, Zhang Y, Grady BP, Capecelatro A, et al (2008) Synthesis and characterization of the physical, chemical and mechanical properties of isocyanate-crosslinked vanadia aerogels. J Sol-Gel Sci Technol 48 113-134... 

Figure 13.12. Scanning electron micrographs of native (A., (B., Pb = 0.420 g cm ) vanadia aerogels.

Crosslinked vanadia aerogels underline the importance of the network morphology in the mechanical behavior of crosslinked aerogels. But vanadia is expensive. Bicontinuous macro/mesoporous materials consisting of entangled worm-Uke nanostmctures perforated by tubular mesopores (Figure 13.15A, B) have been created with acid-catalyzed silica by modification of Nakanishi s procedure [73], which in turn comprises a modification of... 

Figure 22.1. Mechanical compression testing of native silica and native vanadia aerogels.

Figure 22.3A, B depicts the storage modulus, loss modulus, and loss tangent as a function of temperature for polymer crosslinked silica aerogel (X-SiOx) with density 0.67 g/ cm and polymer crosslinked vanadia aerogel (X-VOx) with density 0.65 g/cm. At room temperature (23°C), the Young s modulus is 611/673 MPa for X-SiOx andX-VOx, respectively. As the temperature becomes lower the storage modulus increases. At — 119°C, the...

Volatility Measure of the ease of a substance to vaporize VOx Vanadia aerogels VTMS Vinyltrimethoxysilane... 

---